Line connection speed always fixed

[#1]

Recently my line speed has reduced but also become set at the same level regardless of how I set the gain on the router (Bipac 8800NL) - auto or at various levels.  Currently it always connects at 20000U and 54999D.  I used to get various download speeds up to nearly 80000, differing slightly each time the router was reset.  If I tweaked the gain I could get higher speeds but becoming more unreliable.  I just wondered if it is something that BT have done at the exchange, as it's always the same - the line is rock solid and so I shouldn't complain but I'd just like the old speed.  It might sound cynical, but Openreach are just installing fibre in the area to provide FTTH, and I'm now tempted if I can significantly increase speed, whereas at my old speed I wasn't that bothered.

[#2]

Hello, a warm welcome to the forums.

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@drmih wrote:

If I tweaked the gain I could get higher speeds but becoming more unreliable.  I just wondered if it is something that BT have done at the exchange, as it's always the same - the line is rock solid

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There is real bad Kama in fiddling with the line settings - as you have seen, it can create instability and drastic action from the DLM.

You increasing the gain on your circuit could be detrimental to other users.  Best advice is to leave the settings well alone and leave the DLM to rectify matters itself in the fullness of time.  That is unless the line has been banded, in which case staff intervention will be required.

What's the push for a couple of extra mbps at the risk of being stuck with less?  Invariably at the margins, driving a higher sync speed only leads to a higher error rate and a lower data transfer rate - that is zero advantage!

[#3]

Sorry - I wasn't clear.  I do leave the sync at automatic, but on the Bipac it is possible to tweak it.  The issue is that no matter what value is used when testing (if not automatic), the line speed is always the same.  Historically, whenever the modem was reset / power cut, it would't just get the same download speed, but a different value each time, but similar magnitude (the upload has always connected at 20000).  Therefore it's gone from a value somewhere between 75000 to 80000 to always 54999.

[#4]

Yup it appears to be banded consequent to your observation that tweaking made it go unstable. AFAIK the only variable you can try to tweak is the SNRM to get more speed. You cannot simply “dial” more speed. Looks like the DLM fought back and won.

[#5]

Thanks, but wrong way around.  When I noticed it was fixed at the fixed lower speed after restarting etc, I remembered the option of being able to tweak it (which I had tried about 7 years ago when I first got it).  The tweaking was just to see if it was 'fixed' as even if unstable it should have changed.  Therefore, whatever has led to it being fixed, was nothing to do with the later test tweaking.

When I check the summary, for downloads is has the rate of 54999, but above that it gives an Attainable Rate and that is about 70000 (it changes every few seconds slightly but is in the 69000s).

[#6]

The attainable rate is a theoretical figure assuming that the line is perfect, running with a 6dB SNRM.  In other words, evaluating the instantaneous loss of noise, suggests that the line might run at...

Achieving such requires that the source of noise be identified and eliminated.  Often the attainable speed is little more than a dream.

That said, your line reports 8dB SNRM for no clear reasons - if understood and operation at 6dB were sustainable, you might see more sync speed ... but to what tangible benefit?

[#7]

Thanks.  Now that I think about it, a few months ago BT were in the cabinet and managed to disconnect the line (I noticed whilst they were still working and grabbed them) and they did something in the cabinet, and also opened up the master socket, and got it back again.  However, that might have been when the speed changed.  According to the router the noise is actually 10dB.

[#8]

Raise a broadband speed fault report - see where that takes you.

[#9 · Accepted solution]

Hi there,

Testing your line's not showing any issues so I've arranged for your line to be reset and 55mbps banding to be removed which should hopefully boost your speed back up within the next 3 working days. 

Let us know how it goes.

[#10]

Many thanks - it's already up to 66500.

[#11]

That's great to hear, hopefully it stays that way! Let us know how things go